* We need an extra -funfolding-use-threshold. We don't really want users having to worry about that.

37

40

* `mapP (\x -> x * x) xs` essentially turns into `zipWithU (*) xs xs`, which doesn't fuse with `enumFromTo` anymore. We have a rewrite rule in the library to fix that, but that's not general enough. We really would rather not vectorise the lambda abstraction at all.

41

* `enumFromTo` doesn't fuse due to excessive dictionaries in the unfolding of `zipWithUP`.